Surgical instrument

ABSTRACT

In a surgical instrument comprising a tool which is oscillatingly pivotable about an axis of rotation and a rotatingly driven drive shaft which by means of an eccentric causes an oscillating lever which is rotationally fixedly connected to the tool to pivot oscillatingly back and forth, in order to achieve a simplified adaptation of the pivoting angle to the respective tool, it is proposed that the drive shaft comprise adjacent to each other at least two eccentrics with different eccentricity, that an oscillating lever pivotable about the axis of rotation of the tool be associated with each eccentric, and that the tool be rotationally fixedly connected to only one of the oscillating levers.

This application is a continuation of International Application No.PCT/EP2003/009664 filed on Aug. 30, 2003.

The present disclosure relates to the subject matter disclosed inInternational Application No. PCT/EP2003/009664 of Aug. 30, 2003 andGerman Application No. 102 40 655.3 of Sep. 4, 2002, which areincorporated herein by reference in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a surgical instrument comprising a tool whichis oscillatingly pivotable about an axis of rotation and a rotatinglydriven drive shaft which by means of an eccentric causes an oscillatinglever which is rotationally fixedly connected to the tool to pivotoscillatingly back and forth.

Such surgical instruments are used, for example, for saw blades,trephines, oscillating drills or similar tools. The angle of theoscillating rotary movement of the tools depends on the type of tool.Relatively large pivoting angles are often required for instruments witha small radius. Tools with a large radius, on the other hand, forexample, trephines require relatively small pivoting angles.

With conventional instruments, these different pivoting angles areobtained by use of different handpieces or drive components which make acertain pivoting angle available. There are also handpieces which enableadjustment of the pivoting angle, but a complicated adjusting mechanism,which involves a very complex setup, is required for this.

In all cases there is the danger that owing to selection of a wronghandpiece or owing to wrong adjustment, the user will select a pivotingangle which is unsuitable for the respective tool.

The object of the invention is to so construct a generic instrument thatwith simple means it is ensured that a tool can be operated with thepivoting angle required for this tool.

SUMMARY OF THE INVENTION

This object is accomplished, in accordance with the invention, with asurgical instrument of the kind described at the outset in that thedrive shaft comprises at least two eccentrics with differenteccentricity adjacent to each other, in that an oscillating leverpivotable about the axis of rotation of the tool is associated with eacheccentric, and in that the tool is rotationally fixedly connected toonly one of the oscillating levers.

The surgical instrument thus makes at least two oscillating leversavailable, which are made to pivot oscillatingly with a differentpivoting angle by the drive shaft, and the tool is rotationally fixedlyconnected by suitable means to only one of these oscillating leversrespectively, so that the pivoting angle attainable for this toolcorresponds to that of the corresponding oscillating lever.

In this way, it is, for example, possible, when manufacturing such asurgical instrument, to use a universal instrument, into which differenttools are selectively insertable. The pivoting angle required for theinserted tool is then determined directly by the manufacturer byrotationally fixed connection of this tool with only one of the twooscillating levers.

With this construction, a possibility is, however, particularlyadvantageous, wherein in a single surgical instrument different toolsare rotationally fixedly connected to different oscillating levers.Different tools which have to be operated with different pivoting anglesthus belong to the surgical instrument, and these are designed so as toestablish a rotationally fixed connection only with that oscillatinglever in the instrument which provides the proper pivoting angle for therespective tool. With a single drive shaft, it is thus possible in avery simple way, without any adjustment, to provide different pivotingangles for the different tools.

It is particularly advantageous for the tool in a working position to bereleasably connected to one oscillating lever and to be pullable out ofthis working position out of the instrument. Easy exchange of the toolis thus possible. Upon inserting the tool, this automatically connectswith that oscillating lever which provides the correct pivoting anglefor this tool. Operating errors are excluded, and tools with a differentpivoting angle can be operated with one drive shaft.

It is advantageous for the tool to be securable against axialdisplacement in the pushed-in operating position in the instrument, sothat the rotationally fixed connection with a certain oscillating leveris thereby ensured.

Provision is made in a particularly preferred embodiment for therotationally fixed connection to be formed by radial recesses andprojections which enter into and rest against these recesses incircumferential direction interlocking with one another and allowingaxial displacement of the tool relative to the drive shaft. Therotationally fixed connection can thus be established and releasedsimply by axial displacement of the projections and recesses relative toone another, and this relative displacement is brought about byinserting a tool into the instrument.

It is advantageous for the projection to be formed by an axiallyparallel, radially protruding rib.

The recess is preferably formed by an axially parallel groove.

Provision is made in a particularly preferred embodiment for eachoscillating lever to carry a recess and for each tool to have only oneprojection which is arranged in axial direction along the tool so as toestablish a rotational connection with only one oscillating lever. Whenthe user inserts the tool into the instrument, this projection is thusautomatically located opposite one of the grooves of the oscillatinglevers and establishes a rotationally fixed connection with thisoscillating lever, but not with any other oscillating levers.

It is advantageous for the eccentrics to be arranged in a differentangular position. A balancing of the drive shaft can thereby beeffected, and particularly smooth running of the instrument is thusobtained. In particular, it is advantageous, in the case of twoeccentrics, for these to be offset in opposite direction.

The following description of preferred embodiments of the inventionserves in conjunction with the drawings to explain the invention ingreater detail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a longitudinal sectional view through a surgical instrumentwith two adjacently arranged oscillating levers and a tool coupling withthe rear oscillating lever;

FIG. 2 shows a view similar to FIG. 1 with another tool coupling onlywith the front oscillating lever; and

FIG. 3 shows a sectional view taken on line 3-3 in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The surgical instrument 1 depicted in the drawings comprises a housing2, in which there is mounted in ball bearings 3, 4 a drive shaft 5 whichcarries a drive pinion 6 at one end thereof. The drive pinion 6 mesheswith a pinion 7 on a connecting shaft 8, which is likewise mounted bymeans of ball bearings 9 in the housing 2 and is surrounded by aconnection piece 10 by means of which the housing 2 can be connected toa flexible drive shaft 11. The drive shaft 11 comprises a casing 12 anda rotatable shaft 13 therein, which is rotated by an external drive, notdepicted in the drawings, and which can be rotationally fixedly coupledwith the connecting shaft 8. In this way, the drive shaft 5 can be madeto rotate continuously.

A receiving bore 14 for the shaft 15 of a tool 16 is arranged paralleland adjacent to the drive shaft 5 in the housing 2. This receiving bore14 is open towards the side of the housing 2 facing away from theconnection piece 10, so that the shaft 15 of the tool 16 can be insertedinto the receiving bore 14 from this open side. Inserted in thereceiving bore 14 is a bearing sleeve 17 which is freely rotatable inthe receiving bore 14 and is secured in axial direction in the receivingbore 14 by a transverse pin 18.

A quick coupling 19 engages over the receiving bore 14 at the open endthereof. When the tool 16 is inserted, a locking member 20 of the quickcoupling 19 engages in a circumferential groove 21 of the tool 16 andthereby fixes the tool in axial direction in the bearing sleeve 17 andthus in the receiving bore 14. The locking members 20 can be released ina manner known per se and not described herein in more detail by a gripsleeve 22 being pressed against the action of a spring 23, so that thetool 16 can then be pulled in axial direction out of the bearing sleeve17 and thus out of the receiving bore 14.

The tool 16 may differ in design. In the embodiment shown, a trephinewith a small diameter is depicted in FIG. 1 and a trephine with a largerdiameter in FIG. 2.

Two oscillating levers 25, 26 are rotatably mounted side by side on thebearing sleeve 17 and are separated by a spacer ring 24. Theseoscillating levers comprise a circular bearing ring 27 surrounding thebearing sleeve 17, and two parallel webs 29 forming between them anengagement opening 28 which is open at one side thereof. The webs 29extend on either side of the drive shaft 5. The drive shaft 5 comprisesan eccentric section 30 and 31, respectively, in the region of theoscillating levers 25 and 26. The eccentricity of these eccentricsections 30 and 31 is different. The eccentric sections 30 and 31 areoffset from each other in circumferential direction throughapproximately 180°. Each eccentric section 30, 31 carries a ball bearing32 and 33, respectively.

These ball bearings 32 and 33 engage in the engagement openings 28 ofthe two oscillating levers 25 and 26 with a tight fit, so that uponrotation of the drive shaft 5, both oscillating levers 25, 26 arepivoted oscillatingly to and fro, more particularly, in accordance withthe different eccentricity of the eccentric sections 30 and 31 withdifferent maximum pivoting angle.

An axially parallel groove 34, 35 is arranged in each of the twooscillating levers 25, 26 on the inner side of the bearing ring 27.These two grooves 34 and 35 are oriented in alignment with each other.

An axially parallel slot 38 is arranged in the bearing sleeve 17 in arear section 36 which dips into the bearing rings 27 and has a smallerdiameter than the front section 37 of the bearing sleeve 17. The slot 38narrows in the direction of insertion of the tool 16 and extends beyondthe two oscillating levers 25 and 26.

The tool 16 carries on its shaft 15 a radially protruding catch 39. Whenthe shaft 15 is pushed into the bearing sleeve 17, the catch 39 entersthe slot 38 and a certain guidance is imparted to it therein. When theshaft 15 is pushed in completely, the catch 39 enters groove 34 orgroove 35 of the two oscillating levers 25, 26. Which of the two grooves34, 35 the catch 39 enters will depend on the axial position of thecatch 39 on the shaft 15. In the embodiment of FIG. 1 the catch 39 isarranged such that when the shaft 15 is pushed in completely, the catch39 engages the groove 35 of the rear oscillating lever 26. In theembodiment of FIG. 2, on the other hand, the catch 39 is arranged moretowards the front end of the tools and therefore enters groove 34 of theoscillating lever 25. The catch 39 thus makes a rotationally fixedconnection between the tool 16 and one of the two oscillating levers 25,26. This rotationally fixed connection also includes the bearing sleeve17 as the catch 39 passes through the slot 38. In accordance with therespective pivoting angle of the oscillating lever 25, 26 with whichthis rotationally fixed connection has been made, the tool will then bemade to pivot oscillatingly with a different pivoting angle.

Selection of the correct oscillating lever results automatically fromthe position of the catch on the tool. The user only has to push therespective tool into the housing 2 and secure it in axial direction bymeans of the quick coupling 19. A connection with the “correct”oscillating lever is then made automatically, and the tool is drivenwith that pivoting angle which is suitable for this tool.

Only two such oscillating levers 25, 26 are provided in the embodimentshown. It is, in principle, also possible for more oscillating levers tobe arranged adjacent to one another, each having an eccentric sectionwith a different eccentricity associated therewith and thus a differentpivoting angle. By means of different positioning, the catch 39 on thetools could then selectively choose the pivoting appropriate for therespective tool. This results in a construction which is very easy forthe user to handle. When he pushes a certain tool into the housing 2,the rotational coupling with the correct oscillating lever occursautomatically. The possibility of making a mistake is dispensed with.The tool itself will select the appropriate oscillating lever therefor.

1. Surgical instrument comprising a tool which is oscillatinglypivotable about an axis of rotation and a rotatingly driven drive shaftwhich by means of an eccentric causes an oscillating lever which isrotationally fixedly connected to the tool to pivot oscillatingly backand forth, wherein the drive shaft comprises at least two eccentricswith different eccentricity adjacent to each other, an oscillating leverpivotable about the axis of rotation of the tool is associated with eacheccentric, and the tool is rotationally fixedly connected to only one ofthe two oscillating levers.
 2. Instrument in accordance with claim 1,wherein different tools are rotationally fixedly connected to differentoscillating levers.
 3. Instrument in accordance with claim 1, whereinthe tool in a working position is releasably connected to oneoscillating lever and is pullable out of this working position out ofthe instrument.
 4. Instrument in accordance with claim 3, wherein thetool is securable in the pushed-in working position against axialdisplacement in the instrument.
 5. Instrument in accordance with claim1, wherein the rotationally fixed connection is formed by radialrecesses and projections which enter into and rest against theserecesses in circumferential direction interlocking with one another andallowing axial displacement of the tool relative to the drive shaft. 6.Instrument in accordance with claim 2, wherein the rotationally fixedconnection is formed by radial recesses and projections which enter intoand rest against these recesses in circumferential directioninterlocking with one another and allowing axial displacement of thetool relative to the drive shaft.
 7. Instrument in accordance with claim5, wherein the projection is formed by an axially parallel, radiallyprotruding rib.
 8. Instrument in accordance with claim 5, wherein therecess is formed by an axially parallel groove.
 9. Instrument inaccordance with claim 6, wherein the recess is formed by an axiallyparallel groove.
 10. Instrument in accordance with claim 8, wherein eachoscillating lever carries a recess, and each tool has only oneprojection which is arranged in axial direction along the tool so as toform a rotational connection with only one oscillating lever. 11.Instrument in accordance with claim 5, wherein the angular position ofthe projections and recesses, respectively, on the oscillating levers isthe same.
 12. Instrument in accordance with claim 11, wherein guideswhich narrow in the direction of insertion of the tool are provided torotate the tool such that the projections and recesses are oriented inalignment with one another.
 13. Instrument in accordance with claim 12,wherein the guides are formed by a narrowing longitudinal groove in abearing sleeve surrounding the tool.
 14. Instrument in accordance withclaim 1, wherein the eccentrics are arranged in a different angularposition.
 15. Instrument in accordance with claim 14, wherein in thecase of two eccentrics, these are offset in opposite direction.